Drivers of the 2004 Infiniti G35 often appreciate the blend of sporty performance and daily comfort, yet even this well-regarded luxury coupe is not immune to specific mechanical challenges. While the VK35DE engine is generally robust, owners frequently encounter issues related to aging high-mileage wear, electrical gremlins, and the inevitable wear on consumable components. Understanding these common problems allows for proactive maintenance, helping to preserve the driving dynamics that made the G35 popular in the first place.
Electrical Gremlins and Infotainment Quirks
The 2004 model year sits at a transition point where analog systems began shifting toward early digital interfaces, and this blend can sometimes lead to frustration. Electrical gremlins are a common complaint, manifesting as intermittent faults with the power windows, central locking systems, or dashboard warning lights that appear without a clear cause. These issues are often rooted in corroded connectors or failing relays, requiring a patient approach to diagnosis. Furthermore, the factory infotainment system, while advanced for its time, can experience screen malfunctions or radio static that disrupts the premium audio experience many buyers expected.
Navigation and Audio Head Unit Failures
A specific subset of the electrical system involves the navigation and audio head unit, which can become a significant point of failure. Owners have reported complete system shutdowns, frozen screens, or a sudden inability to read CD discs. In some scenarios, the wiring harness behind the unit can chafe against the chassis, leading to a short that creates erratic behavior. Re-seating the connectors or installing a simple grounding kit often resolves these audio and navigation glitches without the need for expensive head unit replacement.
Engine Performance and the Timing Chain Concern
Under the hood, the 3.5-liter V6 engine delivers smooth power, but long-term reliability can hinge on a specific component: the timing chain. While not every 2004 G35 will experience this, there are documented cases of the timing chain rails wearing down prematurely. This wear can lead to a condition known as "chain slap," which creates a distinct rattling noise, particularly noticeable on cold starts or during idle. If left unaddressed, a stretched or broken chain can cause catastrophic engine damage, making this one of the most critical checks for any used G35.
Valve Cover Gasket and Vacuum Leaks
Another frequent source of under-the-hood noise is a leaking valve cover gasket. The design of the VK35DE engine means these gaskets can dry out and crack over time, allowing oil to seep into the engine bay. This oil can drip onto the hot exhaust manifold, creating a burning smell that worries many new owners. Additionally, vacuum hoses connected to the brake booster and various sensors can become brittle and crack, leading to vacuum leaks that result in a rough idle and decreased fuel efficiency.
Suspension, Brakes, and Steering Wear
As a sport-tuned sedan, the G35's suspension components are constantly working to provide that precise handling feel. However, the bushings and struts are subject to fatigue after years of road abuse. Drivers may notice increased road chatter, a slight drift when cruising, or a "clunk" sound when driving over uneven pavement. Similarly, the braking system requires attention; the stock brake pads can wear quickly if the car is driven aggressively, and the brake lines may need inspection for cracks to ensure safe stopping power.
Steering Rack and Transmission Shifts
The steering rack is another component that can develop play over time, leading to a vague feeling in the front end. Tightening or replacing the rack mounts usually restores the tight, responsive feel the G35 is known for. On the transmission side, the automatic gearbox generally holds up well, but some owners report harsh shifting or hesitation if the transmission fluid is not changed regularly. Using the correct fluid type and adhering to the service schedule is vital for maintaining the smooth power delivery that defines the driving experience.
